Breaking news: Version 0.9 is out, featuring Io/Lua/Perl/PHP/Python/Ruby backends and some changes to the PHP interface.

Sajax is an open source tool to make programming websites using the Ajax framework — also known as XMLHTTPRequest or remote scripting — as easy as possible. Sajax makes it easy to call PHP, Perl or Python functions from your webpages via JavaScript without performing a browser refresh. The toolkit does 99% of the work for you so you have no excuse to not use it.